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Dreaming of Mars Sample ReturnNational Aeronautics and Space Administration Dreaming of Mars Sample ReturnSpace Administration
Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadena, California
Erik M. ConwayOctober 2012
Solar System @ 50
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Threads of this Story
• Design and Engineering in support of science
• Competition for funds within NASA
• NASA’s dual self-image asg– A scientific agency– The enabler of human expansion into the solar system
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Act I: Scientists and Sample Return, 1977-1989
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Act II: Sample Return in the Faster, Better, Cheaper Era
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LANDED CONFIGURATIONHGA
MAV/MAV INSULATIONMAV/MAV INSULATION
SSI
UHF ANTENNA
LGA2 REC &2 TRANSSHOWNS O
ROVER
Y
SOLAR ARRAY2 PLCS
DRILL ENVELOPE
XZ
RAMPS
INSTRUMENT DECKUPPER SURFACE
Report on the Loss ofthe Mars Polar Lander andDeep Space 2 Missions
JPL Special Review Board
22 March 2000
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JPL D-18709
A t IIIAct IIIThe Bubble Team and Large Lander Studies
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Mars Science Laboratory
Evolution from MSR Large Lander to Mars Smart Lander (circa early 2000)
y
Mars 98 & MSR Mars Smart Lander Mars Expl. Rover Mars Science Lab.•EDL architecture given one
•The failure of the M98 lander mission during MSR’s phase A, led to a change in risk posture on landing
b t
•Extensive evaluation of many different EDL and Landing architectures suitable for MSR were t di d
•MSL mission was delayed to 2007 and then 2009, resulting in more time to develop technologies.
last “fresh” look, focused on:Cost ReductionPerformance IncreaseEDL Feed Forward
D i t i t b trobustness.
•Several review boards and tiger teams were assembled to redirect MSR’s landing/EDL architecture.
studied.
•Pallet style landing system with a large rover was selected based on expectation of a 2005
•MER made a large investment in developing multi-body control dynamics.
•MER discovered the hidden challenges and costs of
•Desire to incorporate best lessons and technologies from MER; multi-body control, DRL…
•Further advancement of
PRE-DECISIONAL DRAFT; For planning and discussion purposes only 17
•Robust rover egress for MSR was never addressed.
launch.
•Pallet greatly improved egress and landing safety.
challenges and costs ofegressing a rover.
sensor technologies & HDA
• Sky Crane invented
Mars Science Laboratory
Design Evolution From Tripod to Pallety
Starting Point: •Tripod lander based on Viking heritage. •Deployable ramps required for rover egress.
Modified Tripod 1: od ed pod•Viking tripod with stability enhancing outriggers added.•Deployable ramps required for rover egress.
Modified Tripod 2: •Viking tripod with stability enhancing outriggers added.Viking tripod with stability enhancing outriggers added.•Belly ruggedization for direct rock strikes. •Inflatable ramps for rover egress.
Pallet Concept 1: •Crushable belly with low CG & stability outriggers
Pallet Concept 2: •Crash-worthy belly with KE absorbing struts, very l CG d t bilit t i
Crushable belly with low CG & stability outriggers.•Stretched fabric for rover egress.
low CG and stability outriggers.•Bending members with discrete energy absorption•Stretched fabric for rover egress.
P ll t C t 3
PRE-DECISIONAL DRAFT; For planning and discussion purposes only 18
Pallet Concept 3: •Crash-worthy belly with KE absorbing struts, low CG & stability outriggers.•Cable stayed Tension-Compression outriggers. •Stretched fabric for rover egress.
Mars Science LaboratoryThe “Rocket-on-a-Rope” approach
Airbag System Landing Concepty
System Advantages:-Descent stage never requires engine shut off
-Propulsion hardware does not require impact protection
0.7 m/s
-Improved velocity control (vs Pathfinder & MER missions)
System Disadvantages-Interface complexity between rover and airbags
System self righting and extraction/egress-System self-righting and extraction/egress
PRE-DECISIONAL DRAFT; For planning and discussion purposes only 19
Mars Science Laboratory
Sky Crane System Architecturey
Two-Body ArchitectureDecouples descent stage control from touchdown event and allows persistent
touchdown signature
Prop and GNC Away from SurfaceClosed loop during the touchdown
event
High Bandwidth Vertical Velocity Controlresults in low and near constant D/S velocity
Higher StabilityPersistence of tethering
Lower LoadsLow velocitiesPersistence of tethering
during touchdown improves landing stability on rough
terrain
Low velocitiesallows rover landing loads to be similar to the rovers
driving loads
System DesignSystem DesignHigh stability and low landing loads mean:
• Separate TD system not required• Egress system not required
Rover Becomes the Touchdown System
PRE-DECISIONAL DRAFT; For planning and discussion purposes only 20
Rover Becomes the Touchdown SystemRover provides ground clearance, static
stability, and terrain adaptation
M S i L b t
Design for 2005 Pallet Lander with Long-distance Range Rover
Mars Science Laboratory
Bottom View–Rock nets protect lander propulsion and avionics during touchdown
Top View–Cable-stayed outriggers utilizing load limiters
on the cables to control loads and stability envelope
Pre-decisional, For Discussion Purposes Only
Oct-18-2004 Historical Summary MSL-21
and stability envelope
Act IV: Planning a New Mars Program
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Mars Mobile Pathfinder ‘03
Mark AdlerJoy CrispHoward EisenHoward EisenRob ManningJake MatijevicJake Matijevic
May 3, 2000
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Act V: Whither (or Wither?) The Smart Lander
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of latitudes for surface operations will be limited to approximately 30 degrees about the equator. The mission lifetime and operational activities will also be highly modulated by seasonal controls on amount of sunlight. On the other hand, use of RPS power
“The SDT looked at this opportunity to define the by seasonal controls on amount of sunlight. On the other hand, use of RPS power
systems would allow access to all locations on the planet below the altitude cutoff, with an extended period of operations. A primary mission duration of 180 sols is assumed for solar-powered missions and 360 sols for RPS-powered systems. It is noted that RPS systems could easily provide steady power for up to 720 sols, but that the total cost of the mission would need to increase significantly to accommodate flight systems designed to operate over such a long period of time.
These main characteristics of the Smart Lander Mission were the background for the
pp ySmart Lander Mission as the capstone mission for this decade by making groundbreaking scientific discoveries and paving the g
SDT deliberations. The job of the SDT was to make recommendations focused on science to be accomplished during this landed opportunity and the payloads needed to accomplish the science, and to comment on topics specifically requested in the SDT Charter (Appendix 1). The Smart Lander precision landing, coupled with delivery of a large payload to the surface, offers an opportunity to conduct science on an unprecedented scale on Mars. The SDT looked at this opportunity to define the Smart Lander Mission as the capstone mission for this decade by making groundbreaking scientific discoveries and paving the way for the sample return mission
discoveries and paving the way for the sample return mission.”
scientific discoveries and paving the way for the sample return mission.
3.0 Science Objectives and Measurements Matched to Mis sion Capabilities
The Mars Exploration Payload Analysis Group (MEPAG) has developed a comprehensive strategic plan for exploration of Mars that is focused on the overarching goals of understanding whether or not life got started and evolved, the causes and timing of current and past climates, and the nature and extent of resources available at and beneath the surface [Greeley, 2000]. The role and availability of water is a central theme. Further, a full understanding of life, climate, and resources requir es detailed study of the evolution of the interior, surface, and atmosphere, along with the interplay of various cycles (e.g., climatic and tectonic) that may have dominated Mars during past epochs. All of these results impact our understanding of the ext ent to which surface and near-surface materials can be used to support human expeditions and the extent to which humans need to cope with hazards during their missions.
Th MEPAG d t th t ti i t f SDT d lib ti Th t i th The MEPAG document was the starting point for SDT deliberations. That is, the goals, objectives, investigations, and measurements defined by MEPAG were scrutinized for applicability to the Smart Lander Mission, refined and updated as needed, and used to form the backbone of the science to be accomplished during the 2007 landed opportunity. What follows in this section is a discussion of the science objectives that can be addressed for each of the Mars Exploration Program’s main themes, which are: development and evolution of life, current and past climates, evolution of the surface and interior, and preparation for human expeditions.
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2
, p p p
Mars Science Laboratory
MER Lessons Learnedy
• Multi-bodies tethered system dynamics– The JPL GNC and systems team gained a tremendous amount
of knowledge on dynamics and control of the MER multi-body systemsystem.
• Descent Rate Limiter– New robust DRL device was developed for MER which
increased the teams confidence in using such a device in a critical application.
• Egress Challenge– Extensive development of the MER egress hardware and
operational procedures highlighted the hidden challenges and risks associated with the seemingly simple act of driving off the landerlander.
PRE-DECISIONAL DRAFT; For planning and discussion purposes only 31
Mars Science Laboratory
Can We Have the Best of Both Worlds?y
Airbag w/ Descent Stage System Advantages:-Descent stage never requires engine shut off continuous GNC -Propulsion hardware does not require impact protection-Airbags are a robust, understood means of landing.
Sky Crane Landing System Advantages-Descent stage never requires engine shut off-Propulsion hardware does not require impact protection-Low CG provides stability for large slope landings
Pallet Landing System Advantages:
-Highly decoupled and simple I/Fs between rover and pallet-Low CG provides stability for large slope landings-Rover standup on a known engineered surface no standup-Lower risk egress easier to design and test no egress
PRE-DECISIONAL DRAFT; For planning and discussion purposes only 32
Pallet Landing System Advantages:-Highly decoupled and simple interfaces between rover and pallet-Low CG provides stability for large slope landings-Rover stand-up on a known engineered surface-Lower risk egress easier to design and test
Disadvantages:-Requires bridle deployment mechanism-Requires fly-away maneuver-Requires single nozzle thruster development
Act VI: The Demise of Sample Return, Redux
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Mars Program in Context
Evolution of Mars Budget
Conclusions and Ruminations
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Vision and Voyages for Planetary Science in the Decade 2013-2022
4 VISION AND VOYAGES FOR PLANETARY SCIENCE
TABLE ES.1 Medium-Class Missions—New Frontiers 4 (in alphabetical order)Mi i
“The highest-priority flagship mission for the decade 2013-2022 i th M A t bi l E l Mission
Recommendation Science Objectives Key Challenges Chapter
Comet Surface Sample Return
• Acquire and return to Earth for laboratory analysis a macroscopic (500 cm3) comet nucleus surface sample
• Characterize the surface region sampled• Preserve sample complex organics
• Sample acquisition• Mission design• System mass
4
Lunar South Pole-Aitken Basin Sample Return
Same as 2003 decadal surveya Not evaluated by decadal survey
5
Saturn Probe • Determine noble gas abundances and isotopic ratios of • Entry probe 7
is the Mars Astrobiology Explorer-Cacher (MAX-C), which will begin a three-mission NASA-ESA Mars Sample Return campaign extending into the decade beyond 2022.”
hydrogen, carbon, nitrogen, and oxygen in Saturn’s atmosphere• Determine the atmospheric structure at the probe descent
location
• Payload requirementsgrowth
Trojan Tour and Rendezvous
Visit, observe, and characterize multiple Trojan asteroids • System power• System mass
4
Venus In Situ Explorer Same as 2003 decadal surveya (and amended by 2008 NRC report Opening New Frontiersb)
Not evaluated by decadal survey
5
NOTE: On May 25, 2011, following the completion of this report, NASA selected the OSIRIS-REx asteroid sample-return spacecraft as the third New Frontiers mission. Launch is scheduled for 2016.
y
LARGE MISSIONS
Th hi h t i it fl hi i i f th d d 2013 2022 i th M A t bi l E l C h
third New Frontiers mission. Launch is scheduled for 2016.a National Research Council, New Frontiers in the Solar System: An Integrated Exploration Strategy, The National Academies Press,
Washington, D.C., 2003.b National Research Council, Opening New Frontiers in Space: Choices for the Next New Frontiers Announcement of Opportunity, The
National Academies Press, Washington, D.C., 2008.
The highest-priority flagship mission for the decade 2013-2022 is the Mars Astrobiology Explorer-Cacher(MAX-C), which will begin a three-mission NASA-ESA Mars Sample Return campaign extending into the decade beyond 2022. At an estimated cost of $3.5 billion as currently designed, however, MAX-C would take up a dispro-portionate share of NASA’s planetary budget. This high cost results in large part from the goal to deliver two large and capable rovers—a NASA sample-caching rover and the ESA’s ExoMars rover—using a single entry, descent, and landing (EDL) system derived from the Mars Science Laboratory (MSL) EDL system. Accommodation of two such large rovers would require major redesign of the MSL EDL system, with substantial associated cost growth.
The committee recommends that NASA fly MAX-C in the decade 2013-2022, but only if the mission can be conducted for a cost to NASA of no more than approximately $2.5 billion FY2015. If a cost of no more than about $2.5 billion FY2015 cannot be verified, the mission (and the subsequent elements of Mars Sample Return)about $2.5 billion FY2015 cannot be verified, the mission (and the subsequent elements of Mars Sample Return)should be deferred until a subsequent decade or canceled.
It is likely that a significant reduction in mission scope will be needed to keep the cost of MAX-C below $2.5 billion. To be of benefit to NASA, the Mars exploration partnership with ESA must involve ESA participa-tion in other missions of the Mars Sample Return campaign. The best way to maintain the partnership will be an equitable reduction in scope of both the NASA and the ESA objectives for the joint MAX-C/ExoMars mission, so that both parties still benefit from it.
The second-highest-priority flagship mission for the decade 2013-2022 is the Jupiter Europa Orbiter (JEO). However, its cost as JEO is currently designed is so high that both a decrease in mission scope and an increase in NASA’s planetary budget are necessary to make it affordable. The projected cost of the mission as currently
Copyright © National Academy of Sciences. All rights reserved.
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• My story has several threads– Scientific and engineering ambitions– Robotic vs human spaceflight– Conflicting visions of launch vehicle development
Learning across projects– Learning across projects• Long-term drive for sample return has produced:
– Innovation– Scientific results in related areasScientific results in related areas
• NASA’s duality, it’s schizophrenia, leaves it perpetually torn between scientific mission and what I call it’s colonization mission
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